The invention relates to a method for the treatment of laundry items, with the laundry items being subjected to different successive wet treatments in successive treatment zones.
During wet treatment, particularly during the washing and rinsing of laundry items, liquids are employed which are essentially water. In the case of aftertreatment, for example, a finishing bath of the laundry items, the liquid contains supplements such as finishing agents. At various stages of treatment the unbound liquid (referred to in the trade as xe2x80x9cfree liquorxe2x80x9d) is discharged or separated from the laundry items. At the end of wet treatment a portion of the liquid remaining in the laundry items, the so-called xe2x80x9cbound liquorxe2x80x9d, is separated. Any bound liquor subsequently remaining in the laundry items is removed in the following drying of the laundry items. This drying of the laundry items is very costly in terms of time and energy.
The invention is thus based on the problem of creating a method which simplifies the drying process of the laundry items.
A method for solving this problem is shown in the method disclosed herein. It has been surprisingly shown that by employing a liquid with a higher liquids are employed which are essentially water. In the case of aftertreatment, for temperature in the last state of treatment the laundry items can be dried much easier, and above all much faster, after wet treatment. The water liquid exhibits a smaller degree of surface tension and is less viscous. This means that a larger percentage of liquid or moisture (bound liquor) held in the laundry items after the wet treatment can be mechanically removed from the laundry items. The remaining residual moisture of the laundry items is less that when using the conventional method, where colder liquid, barely above room temperature, is used in the last treatment zone, in particular in aftertreatment.
According to a preferred embodiment of the method, the liquid not bound in the laundry items (free liquor) is discharged before the laundry items are processed in the last treatment zone and replaced by warmer liquid. Processing in the last treatment zone is then carried out with liquid having a warmer temperature so that following this treatment, the liquor bound in the laundry items is of a higher temperature, meaning that after treatment a greater percentage of this bound liquor can be removed from the laundry items by mechanical means, such as by pressing or spin-drying. Thus only a relatively small percentage of the liquid or moisture must be removed from the laundry items in the subsequent drying stage.
It is advantageous to circulate the warmer liquid used in the last treatment zone. To this end the bound liquor largely separated from the laundry items by mechanical means, i.e. the liquid thereby formed, and preferably also the free liquor are circulated, if necessary back to the start of the last treatment zone. The recycled warmed liquid from the last treatment zone is preferably stored temporarily. To this end, the liquid of the bound liquor mechanically separated from the laundry items and in particular the free liquor as well are caught in a storage tank and, whenever needed, are led from it back to the subsequent laundry items at the start of the last treatment zone. The interim storage of the liquid of the bound liquor allows for an intermittent feeding of this liquid to the last treatment zone.
Also provided by the invention are means for reheating the liquid obtained, for example from a hydroextraction press, when it is returned to the start of the last treatment zone and/or in the interim or storage tank. In particular, the liquid is brought to a temperature such that, at the end of the wet treatment of the laundry items in the last treatment zone and in particular when the bound liquor is separated from the laundry items after the last treatment zone, the liquid of the bound liquor still has a temperature high enough which allows for most of the bound liquor to be separated from the laundry items.
According to the invention, the temperature in the last treatment zone is selected to lie in a range 20xc2x0 C. to 40xc2x0 C. above the average outer temperature and/or 10xc2x0 C. to 50xc2x0 C. above the temperature of the liquid at the end of the last treatment zone. Accordingly, the temperature of the liquid in the last treatment zone is approximately 40xc2x0 C. to 80xc2x0 C. For laundry items whose fabric can withstand higher temperatures, the liquid in the last treatment zone can also be greater than 80xc2x0 C.
The temperature of the liquid when it is fed into the last treatment zone is preferably about 60xc2x0 C. In contrast, the temperature of the previous treatment zone is only about 30xc2x0 C.
The stated temperatures of the liquid in the last treatment zone, in particular a temperature in the range of approximately 60xc2x0 C., means that when a portion of the bound liquid is mechanically separated from the laundry items the temperature of the liquid or moisture in the laundry items is always significantly greater than the ambient temperature or the temperature of the liquid at the end of the preceding treatment zone. In practice, this temperature lies only a few degree below the intake temperature of approximately 60xc2x0 C.